A tornado is a violently rotating column of air which is in contact
with both a cumulonimbus cloud base and the surface of the earth.
Tornadoes can come in many sizes, but are typically in the form of a
visible condensation funnel, with the narrow end touching the earth.
Often, a cloud of debris encircles the lower portion of the funnel.
Most tornadoes have winds of 110 mph (175 km/h) or less, are
approximately 250 feet (75 meters) across, and travel a few miles
(several kilometers) before dissipating. However, some tornadoes can
have winds of more than 300 mph (480 km/h), be more than a mile
(1.6 km) across, and stay on the ground for dozens of miles (more than
100 kilometers). Tornadoes have been observed on every continent
except Antarctica; however, most of the world's tornadoes occur in the
United States. Other areas which commonly experience tornadoes include
New Zealand, western and southeastern Australia, south-central Canada,
northwestern and central Europe, Italy, south-central and eastern
Asia, east-central South America, and Southern Africa.
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Today's selected anniversaries:
Peter Minuit bought Manhattan in exchange for trade goods valued at 60
Ecuadorian War of Independence: Troops led by Antonio José de Sucre
secured the independence of Quito from Spain in the Battle of
The Brooklyn Bridge, at the time the longest suspension bridge in the
world, was opened.
World War II: The German battleship Bismarck sank the British
battlecruiser HMS Hood in the Battle of the Denmark Strait.
Project Mercury: American astronaut Scott Carpenter orbited the Earth
three times in the Aurora 7 space capsule.
Wikiquote of the day:
Freedom of expression is the matrix, the indispensable condition, of
nearly every other form of freedom. -- Benjamin N. Cardozo